I teach basic college writing to international students. At times, a student whose English is still weak will come to ask me a question, and I can't understand what the student is asking; or the student will propose an idea, and I can't perceive what the idea is.
The communication problem is not grammar. By the time the students reach the classes I teach, their grammar, while not perfect, is sufficient. The problem is finding the right words that will cue corresponding information in my mind.
For example, today an Asian student wrote this phrase into a paragraph "generate people." Gently I told the student, "I don't understand that phrase." After several minutes of the student talking and me listening, I typed, "a community of people who are united in their beliefs." The student smiled and said, "Yes, that is what I was trying to express."
How did I derive my phrase from "generate people"? By listening, and listening,again, and then again. These students are quite intelligent. Being the type to adventurously undertake a college or graduate degree in a language system utterly different from their own, in a location between 4,000 and 10,000 miles away from home, they are also the type to have quick insights and many original ideas. But which are the most efficient English words for cueing their ideas to arise in an English-speaking reader's mind? I have the privilege of helping them discover those cues and put them to use. My reward is to glimpse the colorful and varied thoughts in the minds of my colorful, varied students.